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Oral sex and sexually transmitted infections

Information about oral sex, the risk of getting and passing on sexually transmitted infections through oral sex, how to get tested and treated if you think you have an infection, and how to protect yourself.

Many people believe you cannot get a sexually transmitted infection through oral sex, but it is possible.

You can only pass on an infection if you already have one, and you can only get an infection if a partner has an infection. Many people do not get or notice signs or symptoms, and do not know they have an infection.

Infections can be passed on through oral sex in a number of ways:

Skin to skin, or hair to hair, contact

Herpes simplex can cause cold sores on the mouth and blisters on the genitals, and syphilis can cause open sores or a skin rash. If these touch a partner’s mouth, genitals or anus the infection may be passed on. Sometimes the infection can be passed on through skin to skin contact without there being any symptoms.

It is rare for genital warts to be passed to the mouth and lips through oral sex.

Pubic lice can be passed between pubic hair and any coarse facial hair, such as a beard.

Body fluids

The viruses or bacteria that cause some infections can be passed on in infected body fluids such as semen, pre-ejaculatory fluid (pre-cum), blood, or vaginal secretions.

Infection can occur if infected body fluids come into contact with:

sores, cuts, ulcers, or inflamed cells on the lips, mouth, genitals or anus

the membrane of the eye

the cells of the throat.

This contact allows the viruses or bacteria to enter the blood stream or to live in the cells. Chlamydia, gonorrhoea, hepatitis B, hepatitis C, HIV and syphilis can be passed on in this way.

Ingestion (eating)

Hepatitis A is an infection of the gut that is passed on through infected faeces (shit). It can be passed on through licking or touching a partner’s anus even if their anal area looks clean.

Yes, you could be at risk of an infection if you have licked, kissed or sucked a partner’s penis, vulva, vagina or anus. Infections that are more easily passed on this way include gonorrhoea, Herpes simplex, hepatitis A, hepatitis B and syphilis, although others can be passed on too.

If a partner has an infection they are more likely to pass it on to you if:

you have a sore throat or sores, cuts, ulcers or inflamed skin around or on your lips, or in your mouth

they have blisters, sores, cuts, ulcers, a skin rash or warts on the genitals or anus

your lips or mouth come into contact with the skin where a blister or sore is about to appear

Genital herpes blisters and cold sores (which occur around the mouth and nose) are both caused by the Herpes simplex virus. Oral sex is a very common way for the Herpes simplex virus to pass from one person to another.

If your partner has the Herpes simplex virus in the genitals, this can pass to your mouth if you give them oral sex, and you may get a cold sore(s). The herpes virus doesn’t spread from your mouth to your own genitals, although during your first outbreak of herpes it is possible to transfer it on your fingers if you touch the cold sore and then your genitals.

If a partner is infected with the Herpes simplex virus around the mouth (which can give them a cold sore) and gives you oral sex, the virus can pass to your genitals.

The exact risk of infection is not known. If he has an infection that can be passed on through semen or blood (which can be present in semen) you are probably at more risk if he ejaculates in your mouth. The risk is probably the same whether you swallow the semen or spit it out. The more time his penis and/or semen is in your mouth, the greater the risk.

Infections passed on through semen include chlamydia, gonorrhoea, hepatitis B and HIV.

Pre-ejaculatory fluid (pre-cum) can also carry infection, so you could be at risk if a partner’s pre-cum gets in your mouth, even if he doesn’t ejaculate in your mouth.

If you ejaculate into a partner’s mouth, this does not increase the risk of an infection being passed on to you.

If a partner is HIV positive and ejaculates in your mouth, you have a small risk of getting HIV. The risk depends on how much active HIV infection is in his bloodstream. It also depends on whether you have any cuts, sores or ulcers in your mouth or on your lips.

If you are worried after having sexual contact with an HIV positive partner, you can go to a genitourinary medicine (GUM) clinic, a sexual health clinic or an A&E department. The doctor or nurse will assess your situation to see whether taking anti-HIV drugs, known as Post Exposure Prophylaxis (PEP), would be helpful for you. PEP is more effective the sooner it is used. The latest it can be given is 72 hours after the oral sex happened.

If a woman has an infection that can be passed on through blood there will be a higher risk if you give her oral sex when she has her period. The infection will be more likely to pass to you if you have any sores, cuts, ulcers or inflammation in or around your mouth.

Infections passed on through blood include hepatitis B, hepatitis C and HIV.

Research is currently looking at the link between oral sex and mouth and throat cancer. Mouth and throat cancer has been linked to some types of virus called human papilloma virus (HPV), which can be passed on through sexual contact, including oral sex. These are not the same types of HPV that cause genital warts.

Yes, you could be at risk of an infection if a partner has licked, kissed or sucked your penis, vulva, vagina or anus. You will not be exposed to their genital fluids, so it is thought that the risk of getting an infection is lower than if you perform oral sex.

When you receive oral sex, infections can pass to you if a partner has a sexual infection that can give them blisters or sores on the lips or in the mouth, or a sore throat, or if blood from a partner’s mouth or lips gets into your body.

It is easier for the infection to pass to you if you have sores, cuts, ulcers or inflamed skin around your genitals and anal area.

Infections that can be passed on by receiving oral sex include herpes, gonorrhoea, syphilis, chlamydia, hepatitis B and HIV.

Although it is possible to detect HIV in urine and saliva, the level of virus in these fluids is thought to be too low to be infectious. In addition, saliva contains protective substances which reduce the likelihood of the virus being passed on. But if the saliva has blood in it, from cuts in the mouth for example, or from unhealed piercings, then this can make infection possible.

Gums sometimes bleed after you brush your teeth, so try to avoid brushing or flossing your teeth immediately before or after oral sex.

A dam (sometimes called a dental dam) is a latex or polyurethane (soft plastic) square, about 15cm by 15cm, which you can use to cover the anus or female genitals. It acts as a barrier to help prevent sexually transmitted infections passing from one person to another.

You can get dams at some genitourinary (GUM) and sexual health clinics, some contraception clinics, through mail order, or pharmacies may order them for you. They are available in different flavours.

How to use a dam

Cover the genital area (vulva, vagina or anus) with the dam before there is any contact with the mouth.

Hold it in place during oral sex.

It doesn’t matter which side you put against the vulva or anus, but do not turn the dam over once you’ve started using it.

Don’t move a dam from the anus to the vulva because bacteria that are harmless in the anus can cause infection in the vagina.

Do not use oil-based lubricants with latex products as this can damage them. You can use water-based lubricants with latex dams, and it is safe to use oil-based lubricants with polyurethane dams.

You can get confidential help and advice, and all tests and treatments, at a genitourinary medicine (GUM) or sexual health clinic. Your general practice, contraception clinics, young people’s services and some pharmacies may also provide testing for some infections. If they can’t provide what you need, they should be able to give you details of the nearest service that can.

Resource(s)

This website can only give you general information about sexually transmitted infections. The information is based on evidence-based guidance produced by The British Association for Sexual Health and HIV (BASHH).

Remember – contact your doctor, practice nurse or a clinic if you are worried or unsure about anything.